Electrodeposition of nickel from an acid bath



Patented Feb. 21, 1940.

PATENT OFFICE ELEOTRODEPOSITION 0F NICKEL AN ACID BATH Henry amen, Detroit, Mich, aasiznor to The Udylite Corporation, Detroit, Mich a corporation of Delaware No Drawing.

Application December 1, 1939,

.Serial No. 307,080

31 Claims.

This invention relates to the electrodepositlon of nickel from an acid bath.

The object of this invention is to decrease the grain size and increase the lustre of the nickel deposit without decreasing appreciably the duotility of the plate or the current density range of the nickel bath.

I have found that this object can be accomplished by the addition of certain organic compounds to the standard nickel plating baths. The compounds are the ones which contain the sulphonamide or sulphonimide group SO2.N=.

In table I are listed' a number of compounds containing the sulphonamide or the sulphonimide group which produce the result sought to be achieved provided the compound is soluble in the nickel solution. These organic sulphonamides and sulphonimides contain incommon the -SO2.N= group. They may be classified as compounds containing the -'-S0z.N= group. These organic sulphonamides and sulphonimldes contain in common the SO2.N= group attached to carbon linked by the alternate double bond sequence constltutingthe nucleus of the aromatic series. These compounds may, therefore, also be classified as containing in common the group. This structure, for example, is present in:

1. Benzene sulphonamide 2. o-Benzoic sulphonimide 3. {Ii-naphthalene sulphonamide A N l l. 1 1 I The strength 01' the bond between the carbon and sulphur linkage appears important. It is modified by other active groupspresent and the rest of the structure of the molecule. ample, a naphthalene sulphonamide gives much greater brightness and over a wider current density range than an equal concentration of 3- naphthalene sulphonamide. The odor of naphthalene is apparent at the cathode with o: naphthalene sulphonamide, but is not apparent with the beta compound. In fact the alpha derivative is somewhat too active and unstable during electrolysis for best practical results. This result is in keeping with the generally greater stability of other beta naphthalene derivatives compared to the alpha, and their general and rather striking difierences in chemical properties. The benzene series of sulphonamides as to be expected, shows greater regularity, and the brightening action is more commensurate with the solubility of the compound in the nickel bath. In general, the greater the concentration of the compound, the wider is the current density range in which the brightening action is produced. With the less soluble (0.5 g./l. or less) sulphonamides, such as p naphthalene sulphonamide, p-toluene sulphonmethylamlde, pp biphenyl disulphonamide, benzene metadisulphonamide, the

brightening action is manifested mainly in the lower current density areas, whereas the more soluble compounds show their brightening action at all plating current densities. Therefore, from the practical standpoint, it is preferred to use the more soluble compounds such as benzene sulphonamide, o and p-tcluene sulphonamide and o-benzolc sulphonimide. In general, these compounds can be used up to saturation to give beneficial results. However, all of these compounds even with concentrations in the neighborhood of 0.1 g. /l. produce the desired results at the low current densities; therefore, even the slightly soluble compounds produce desirable results.

Table I also contains the optimum concentra For ex 1 Table I ductile and adherent coating can be obtained and within wider current density limits. upon which chromium may easily be applied. The sulphonamides or sulphonimides also decrease the sensisulphmmidi' (88L) tivity of the plating to otherwise harmful concentrations not only of zinc and cadmium but to such other ions that may plate out or be in- 0.11.00 cluded in the plate such as copper, arsenic, seleni- 'g gg g ggj g gfi' um, tellurium and mercury. The sensitivity to or p-Benzoicsulpliondichloramide, .5-1 g./l. (sat) small amounts of harmful organic colloids which a 'ufiifi k, 1.1 3 gJL (581;) may cause poor bond and brittle plate is also dea it???tent lifiti a ttltiifii K321225332 fi ffi i w r ai (saw in the bath, will adhere after the addition of a 8g? gg ggg ga gggggjg soluble sulphonamide or sulphonimide to the bath. pu n gf a Inlwlubla 0K 88 This does not mean, however, that a still larger i i' i iiig meo u m, v.2 slight] soluble excess of colloid would not be harmful or even cmcumsoa-Nflc 3 and 1888118 exceedingly harmful, but that the harmful efp-Toluene sulphouethylamlde, Insoluble Ha.CuH4.SO:.NHC:Ht fects are not as critical as in the absence of the 'gffifififiif sulphonamides. it was observed, for example, p-p g g g z sfi (Bah) that the covering power in deep recesses (low Benzene 1.2a; di su iph onamlde, .5 g./l. (5st.) current dgnsity areas) of a hot Watts bath freshly ggi figg jggfi 35 gm made up from commercial nickel salts was imcmrg s 1. Y h we 5 ,1 (m poved by the addition of toluene sulphonamide. r z itn esdfir m mm shows in another way its eflect upon impuria a 7 F. 9 smpalsq Formula gJl. Formula g./l. (t.

1 300 45 Ha'BOl (borlc acid) 2-6 0.75 2 r. 300 H2130: 1-5 10400 75 225 2-6 -85 4..." s00 45 3-0 10-60 zootoaoo 45 2-0 w-so o.. 300 is C4Ha0-O0OH(ful'01080l(1) an 3. 10.60 300 45 H3120. 40 MKSOGJHQONH 125 75-160 2-6 10-60 75 {filth-55333133113: W 75 M 9... 75 3:130: g% ii 75 5.5 10-25 10 100 H130} 15 NHlCl 75 5.3 5-20 These addition agents are preferably used in ties which are the cause of the poor color or lack the type of grey-nickel bath which produces ducof plate in the recesses. tile, soft, adherent nickel deposits of any thick- The presence of sodium and ammonium salts ness. The baths should preferably be capable is not desirable as a general rule. However, the of operating warm in order to obtain higher consulphonamides alone can be used with beneficial ductivity and therefore higher current densities. efiects in any nickel plating bath that is giving Baths Nos. 1-7 in Table II are typical of nickel satisfactory commercial plates for any given purplating baths of preferred formulations. pose, such as baths 8 through 10 in Table II.

The additions of small quantities of zinc and In the presence of zinc or cadmium ions the cadmium ions to the nickel solutions containing sodium and ammonium salts give rise to more the sulphonamides produce a very marked inbrittle and poorly adherent plate. Vice-versa, crease in the rate of brightening and lustre. less zinc or cadmium is tolerated in the presence While cadmium and zinc salts have been used preof sodium or ammonium ions. For example, while viously as brighteners in plain nickel solutions 3 to 4 gJl. of Na2SO4 or (NHi) 2SO4 produce no without the organic addition agents mentioned appreciable harm when maximum allowable zinc here, they have not proved generally successful or cadmium is present, much higher concentra-' especially Where heavier thicknesses of nickel were demanded. The slightest excess of these ions caused dark streaks in the plate and skipping of plate in the recesses or low current density areas. Furthermore, the brightest plates obtained are very hard and brittle, and if plated to a thickness of .0005" and over as required by todays specifications, the danger of peeling of the coating is very great, especially with the subsequent application of chromium plate over such nickel coatings where the additional stress will cause the coating to crack and lift from the basis metal.

The presence of the sulphonamides changes these conditions, and a much brighter and more tions will produce hard, brittle, poorly adherent plate of poor color and which stain easily. This is much more marked in the warm baths. Sodium salts are less critical than ammonium salts and magnesium salts are much less critical.

The best bufiers are boric and formic acids. Furoic acid and fluoboric acid may be used, but acetic and citric are not recommended because they interfere with the brightness of the deposit.

The preferred baths Nos. 1-7 listed in Table II are operated with l-3 g./l. of benzene sulphonamide or p-toluene sulphonamide or others of the more soluble sulphonamides or a mixture of two. The concentration of zinc or cadmium that can be used with the sulphonamide will depend on the temperature and the pH of the bath, concentration .oi' nickel ions, concentration of buil'er, and to a certain extent on type of sulphonamide or sulphonimide. In general, up to about 0.3 gull. of zinc or up to about .4 g./l. of cadmium may be used in warm baths 1 to '7 listed in Table II; The usual operating temperatures are 100-160 F. and at pH values of 2.5-4.5. The lower pH values are used with higher temperatures.

The sulphonamides produce bright nickel plate over smooth bufled basis metals, such as buffed brass, and the nickel plate needs no subsequent builing even when plated several thousandths of an inch thick.

The various sulphonamides and sulphonimides are mutually compatible and mixtures can be employed in the baths often to an advantage.

This application is a continuation in part of application Serial No. 162,696, filed September 7, 1937.

I claim:

1. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising. essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, in the presence of a compound soluble in the acid nickel solution and containing the group SO2.N=.

2. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, in the presence of a compound containing the group -SOz.N=, which compound is soluble in the solution and has a concentration in the acid nickel solution falling within the range from .1 gram per liter of solution to saturation.

3. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aque-- ous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture range of .1 gram per liter of solution to saturation.

4. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially nickel sulphate,v nickel chloride and boric acid having a pH falling within a range of from about 2 to about 6 electrometric in the presence of a compound containing the group SO2.N=, which compound is soluble in the solution and has a concentration in the solution falling within a range of .1 gram per liter of solution to saturation.

5. A method for electrodepositing nickel to ob-' tain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid solution comprising essentially nickel sulphate, nickel chloride and boric acid containing about 60 to 75 grams per liter of nickel,

about 15 grams per liter oi chloride, about to 37.5 grams per liter of boric acid, and havin a pH falling within a range from about 2 to about 6 electrometric in the presence of a compound containing the group --SO:.N=, which compound is soluble in the solution and is present in the solution in amounts falling within arange from about .1 gram per liter of solution to saturation.

6. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aque-" ous acid nickel solution comprising essentially boric acid and a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel chloride and nickel sulphate, in the presence of a compound soluble in the acid nickel solution and containing the group -SO2.N= and in the presence of a cadmium salt in an amount corresponding to less than about .4 gram cadmium per liter of solution.

7. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially boric acid and a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixure of nickel sulphate and nickel chloride, in the presence of a compound soluble in the acid nickel solution and containing the group --SO2.N= and in the presence of a zinc saltin an amount corresponding to less than about .3 gram zinc per liter of solution.

, 8. A bath for electrodepositing nickel to obtain a time grained lustrous deposit comprising an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having dissolved therein a compound. containing the group SO2.N=.

9. A bath for electrodepositing nickel to. obtain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having dissolved therein a compound containing the group SO2N= in amounts falling within a range of from .1 gram per liter of solution to saturation.

10. A bath for electrodepositing nickel to obtain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising essentially boric acid and a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having a pH falling within a range of from about 2 to about 6 electrometric and having dissolved therein a compound containing thev group -SO2.N= in amounts falling Within a range of from .1 gram per liter of solution to saturation.

acid and containing D-toluene sulphonchloramide.

13. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having a pH falling within a range of from about 2 to about 6 electrometric in the presence of a compound containing the group which compound is soluble in the solution and has a concentration in the solution falling within a range of .1 gram per liter of solution to saturation, and a small amount of a metal from the group consisting of zinc and cadmium.

14. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having a pH falling within a range of from about 2 to about 6 electrometrlc in the presence of a compound containing the group --SO2.N=, which compound is soluble in the solution and has a concentration in the solution falling within a range of .1 gram per liter of solution to saturation, and maintaining the temperature of the solution within a range'from about 15 C. to about 55 C., and a small amount of a metal from the group consisting of zinc and cadmium.

15. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially boric acid and a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture oi? nickel sulphate and nickel chloride, having a pH falling within a range of from about 2 to about 6 electrom'etric in the presence of a compound containing the group SO2.N'=, which compound is soluble in the solution and has a concentration in the solution falling within a range of .1 gram per liter of solution to saturation, and maintaining the temperature of the solution within a range from about 15 C. to about 55 0., and a small amount of a metal from the group consisting of zinc and cadmium.

16. A bath for electrodepositing nickel to obtain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising essentially nickel sulphate, nickel chloride and boric acid having a pH falling within a range of from about 4 to about 5.3 electrometric and having dissolved therein a compound containing the group SO2.N= in amounts falling within a range of from .1 gram per liter oi solution to saturation, and a small amount of a metal from the group consisting of zinc and cadmium.

1'7. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride,

in the presence of a compound soluble in the acid nickel solution and containing the group 18. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising thestepof electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, in the'presence of a compound containing the ro p which compound is soluble in the solution and has a concentration in the acid nickel solution falling within the range of from .1 gram per liter of solution to saturation.

19. A bath for electrodepositing nickel to ob tain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising essentiallya material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having dissolved therein a compound containing the group 20. A bath for electrodepositing nickel to ob tain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture oi nickel sulphate and nickel chloride, having dissolved therein a compound containing the group the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, in the presence of an aromatic compound containing the group SO2.N=, which compound has a concentration in the acid nickel solution falling within the range from .1 gram per liter of solution to saturation.

23. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having a pH falling within a range of from about 2 to about 6 electrometric in the presence of an aromatic compound containing the group SO:.N=, which compound is soluble in the solution and has a concentration in the solution falling within a range of .1 gram per liter of I 37 ing of boric acid, formic acid, furoic acid and 24. A bath for electrodepositing nickel to ob-- solution to saturation.

tain' a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising es' sentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having dissolved therein an aromatic compound I containing the group --SO:.N=.

25. A bath for electrodepositing nickel to obtain a fine grained lustrous deposit comprising an aqueous acid nickel solution comprising 'essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, having dissolved therein an aromatic compound containing the group SO:.N= in amounts falling within a range of from .1 gram per liter of solution to saturation.

26, A method for electrodepositing nickel to obtain a line grained lustrous deposit comprising the step 01 electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride, and a material selected from the group consisting oi boric acid, formic acid, iuroic acid and iluoboric acid, having a pH falling within a range of from about 2 to about 6 electrometric in the presence of a compound containing the'grcup mixture oi nickel sulphate and nickel chloride,

having dissolved therein a compound containing the mm mixture of nickel sulphate and nickel chloride,

anda material selected from the group consistfluoboric acid, in the presence of a compound soluble in the acid nickel solution and containing the group --SO2.N=.

29. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting 01 nickel sulphate, nickel chloride, and a mixture of nickel sulphate and nickel chloride. and a material selected from the group consisting or boric acid, formic acid, i'urolc acid and fluoboric acid, in the presence of an aromatic compound containing the group -SO:.N-=, which compound is soluble in the solution and has a concentration in the acid nickel solution falling within the range 01' from .1 gram per liter of solution to saturation.

30. A method for electrodepositing nickel to obtain a fine grained lustrous deposit comprising the step of electrodepositing nickel from an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulphate, nickel chloride. and a mix.- ture of nickel sulphate and nickel chloride, and a material selected from the group consisting oi.

boric acid, formic acid, i'uroic acid and fluoboric' acid, in the presence 01. a compound soluble in the acid nickel solution and containing the group may snow. 

